Container handling vehicle with first and second sections and larger wheel motors on two of the wheels in the second section

ABSTRACT

A container handling vehicle for picking up storage containers from a three-dimensional grid of an underlying storage system includes a first set of wheels for moving the vehicle along an X direction on a rail system of the grid; and a second set of wheels for moving the vehicle along a Y direction on the rail system of the grid. The Y direction is perpendicular to the X direction. The container handling vehicle includes vehicle body including sides. The vehicle body has a vehicle body footprint defined by horizontal peripheries in the X and Y directions of the vehicle body and includes a first section and a second section. The first section has a first footprint and the second section has a second footprint. The first and second footprints are defined by horizontal peripheries in the X and Y directions of the first and second sections respectively. The first section and the second section are arranged side-by-side, separated by a separation element of the first section, such that a total area of the first and second footprints equals a total area of the vehicle body footprint, and a centre point of the first footprint is arranged off centre relative a centre point of the vehicle body footprint. The first section defines a storage container receiving space which is configured to accommodate a storage container. The second section has a rectangular footprint and includes a portion of a first side of the vehicle body and an opposed portion of a second side of the vehicle body. The second section extends adjacent the separation element. Two wheels are mounted to the separation element. One wheel is mounted to the portion of the first side of the vehicle body and one wheel is mounted to the portion of the second side of the vehicle body. The wheels mounted to said portions of the first and second sides of the vehicle body are driven by a wheel motor that extends from an interior face of the side of the vehicle body into an internal space within the second section.

The present invention relates to the field container handling vehiclesfor automated storage and retrieval systems and to automated storage andretrieval systems comprising such container handling vehicles.

BACKGROUND

The Applicant's already known AutoStore system is a storage systemcomprising a three-dimensional storage grid structure wherein storagecontainers/containers are stacked on top of each other to a certainheight. Such a prior art system is shown in FIG. 1. The storage systemis disclosed in detail in for instance NO317366 and WO 2014/090684 A1.

FIG. 1 discloses a framework structure of a typical prior art automatedstorage and retrieval system 1 and FIGS. 2a and 2b disclose knowncontainer handling vehicles of such a system.

The framework structure comprises a plurality of uprightmembers/profiles 2 and a plurality of horizontal members 3, which aresupported by the upright members 2. The members 2, 3 may typically bemade of metal, e.g. extruded aluminium profiles.

The framework structure defines a storage grid 4 comprising multiplegrid opening/columns 12 arranged in rows. A majority of the grid columns12 are storage columns 5 in which storage containers 6, also known ascontainers or bins, are stacked one on top of another to form stacks 7.Each storage container 6 (or container for short) may typically hold aplurality of product items (not shown), and the product items within astorage container 6 may be identical, or may be of different producttypes depending on the application. The framework structure guardsagainst horizontal movement of the stacks 7 of storage containers 6, andguides vertical movement of the containers 6, but does normally nototherwise support the storage containers 6 when stacked.

The upper horizontal members 3 comprise a rail system 8 arranged in agrid pattern across the top of the grid columns 12, on which rail system8 a plurality of container handling vehicles 9 are operated to raisestorage containers 6 from and lower storage containers 6 into thestorage columns 5, and also to transport the storage containers 6 abovethe storage columns 5. The rail system 8 comprises a first set ofparallel rails 10 arranged to guide movement of the container handlingvehicles 9 in a first direction X across the top of the frame structure,and a second set of parallel rails 11 arranged perpendicular to thefirst set of rails 10 to guide movement of the container handlingvehicles 9 in a second direction Y, which is perpendicular to the firstdirection X, see FIG. 3. In this way, the rail system 8 defines an upperend of the storage columns 5, above which the container handlingvehicles 9 can move laterally above the storage columns 5, i.e. in aplane, which is parallel to the horizontal X-Y plane.

Each container handling vehicle 9 comprises a vehicle body 13 and firstand second sets of wheels 22, 23 which enable the lateral movement ofthe container handling vehicle 9, i.e. the movement in the X and Ydirections. In FIG. 2, two wheels in each set are visible. The first setof wheels 22 is arranged to engage with two adjacent rails of the firstset 10 of rails, and the second set of wheels 23 arranged to engage withtwo adjacent rails of the second set 11 of rails. One of the set ofwheels 22, 23 can be lifted and lowered, so that the first set of wheels22 and/or the second set of wheels 23 can be engaged with theirrespective set of rails 10, 11 at any one time.

Each container handling vehicle 9 also comprises a lifting device 18(not shown in FIGS. 1 and 2 a, but visible in FIG. 2b ) for verticaltransportation of storage containers 6, e.g. raising a storage container6 from and lowering a storage container 6 into a storage column 5. Thelifting device 18 comprises a lifting frame (not shown in FIG. 2a , butsimilar to the one shown in FIG. 2b labeled 17) which is adapted toengage a storage container 6, which lifting frame can be lowered fromthe vehicle body 13 so that the position of the lifting frame withrespect to the vehicle body 13 can be adjusted in a third direction Z,which is orthogonal the first direction X and the second direction Y.

Conventionally, and for the purpose of this application, Z=1 identifiesthe uppermost layer of the grid 4, i.e. the layer immediately below therail system 8 (in the present application, the rail system 8 is termedthe top level of the grid), Z=2 is the second layer below the railsystem 8, Z=3 is the third layer etc. In the embodiment disclosed inFIG. 1, Z=8 identifies the lowermost, bottom layer of the grid 4.Consequently, as an example and using the Cartesian coordinate system X,Y, Z indicated in FIG. 1, the storage container identified as 6′ in FIG.1 can be said to occupy grid location or cell X=10, Y=2, Z=3. Thecontainer handling vehicles 9 can be said to travel in layer Z=0 andeach grid column 12 can be identified by its X and Y coordinates.

Each container handling vehicle 9 comprises a storage compartment orspace for receiving and stowing a storage container 6 when transportingthe storage container 6 across the grid 4. The storage space maycomprise a cavity 21 arranged centrally within the vehicle body 13, e.g.as is described in WO2014/090684A1, the contents of which areincorporated herein by reference.

Alternatively, the container handling vehicles may have a cantileverconstruction, as is described in NO317366, the contents of which arealso incorporated herein by reference.

The single cell container handling vehicles 9 may have a footprint F,i.e. a horizontal periphery in the X and Y directions (see FIG. 4),which is generally equal to the lateral or horizontal extent of a gridcolumn 12, i.e. the periphery/circumference of a grid column 12 in the Xand Y directions, e.g. as described in WO2015/193278A1, the contents ofwhich are incorporated herein by reference. Alternatively, the containerhandling vehicles 9 may have a footprint which is larger than thelateral extent of a grid column 12, e.g. as disclosed inWO2014/090684A1.

The rail system 8 may be a single-track system, as shown in FIG. 3.Preferably, the rail system 8 is a double-track system, as shown in FIG.4, thus allowing a container handling vehicle 9 having a footprint Fgenerally corresponding to a lateral extent of a grid column 12 totravel along a row of grid columns in either an X or Y direction even ifanother container handling vehicle 9 is positioned above a grid column12 adjacent to that row.

In a storage grid, a majority of the grid columns 12 are storage columns5, i.e. grid columns where storage containers are stored in stacks.However, a grid normally has at least one grid column 12 which is usednot for storing storage containers, but which comprises a location wherethe container handling vehicles can drop off and/or pick up storagecontainers so that they can be transported to an access station wherethe storage containers 6 can be accessed from outside of the grid ortransferred out of or into the grid, i.e. a container handling station.Within the art, such a location is normally referred to as a “port” andthe grid column in which the port is located may be referred to as aport column.

The grid 4 in FIG. 1 comprises two port columns 19 and 20. The firstport column 19 may for example be a dedicated drop-off port column wherethe container handling vehicles 9 can drop off storage containers to betransported to an access or a transfer station (not shown), and thesecond port 20 column may be a dedicated pick-up port column where thecontainer handling vehicles 9 can pick up storage containers that havebeen transported to the grid 4 from an access or a transfer station.

When a storage container 6 stored in the grid 4 disclosed in FIG. 1 isto be accessed, one of the container handling vehicles 9 is instructedto retrieve the target storage container from its position in the grid 4and transport it to the drop-off port 19. This operation involves movingthe container handling vehicle 9 to a grid location above the storagecolumn 5 in which the target storage container is positioned, retrievingthe storage container 6 from the storage column 5 using the containerhandling vehicle's lifting device (not shown, being internally arrangedin a central cavity of the vehicle, but similar to the lifting device 18of the second prior art vehicle of FIG. 2b ), and transporting thestorage container to the drop-off port 19. A second prior art vehicle 9is shown in FIG. 2b to better illustrate the general design of thelifting device. Details of the second vehicle 9 are described in theNorwegian patent NO317366. The lifting devices 18 of both prior artvehicles 9 comprise a set of lifting bands connected close to thecorners of a lifting frame 17 (may also be termed a gripping device) forreleasable connection to a storage container. To raise or lower thelifting frame 17 (and optionally a connected storage container 6), thelifting bands are spooled on/off at least one rotating lifting shaft ordrum (not shown) arranged in the container handling vehicle. Variousdesigns of the at least one lifting shaft are described in for instanceWO2015/193278 A1 and PCT/EP2017/050195. The lifting frame 17 featurescontainer connecting elements for releasably connecting to a storagecontainer, and guiding pins. If the target storage container is locateddeep within a stack 7, i.e. with one or a plurality of other storagecontainers positioned above the target storage container, the operationalso involves temporarily moving the above-positioned storage containersprior to lifting the target storage container from the storage column.This step, which is sometimes referred to as “digging” within the art,may be performed with the same container handling vehicle that issubsequently used for transporting the target storage container to thedrop-off port 19, or with one or a plurality of other cooperatingcontainer handling vehicles. Alternatively, or in addition, theautomated storage and retrieval system may have container handlingvehicles specifically dedicated to the task of temporarily removingstorage containers from a storage column. Once the target storagecontainer has been removed from the storage column, the temporarilyremoved storage containers can be repositioned into the original storagecolumn. However, the removed storage containers may alternatively berelocated to other storage columns.

When a storage container 6 is to be stored in the grid 4, one of thecontainer handling vehicles 9 is instructed to pick up the storagecontainer from the pick-up port 20 and transport it to a grid locationabove the storage column 5 where it is to be stored. After any storagecontainers positioned at or above the target position within the storagecolumn stack have been removed, the container handling vehicle 9positions the storage container at the desired position. The removedstorage containers may then be lowered back into the storage column, orrelocated to other storage columns.

For monitoring and controlling the automated storage and retrievalsystem, e.g. monitoring and controlling the location of respectivestorage containers within the grid 4, the content of each storagecontainer 6 and the movement of the container handling vehicles 9 sothat a desired storage container can be delivered to the desiredlocation at the desired time without the container handling vehicles 9colliding with each other, the automated storage and retrieval systemcomprises a control system, which typically is computerized andcomprises a database for keeping track of the storage containers.

The prior art solutions include both so-called cantilever robots andsingle cell robots. The cantilever robots may have available space forlarger motors, however the robots may be more unstable than their singlecell counterparts. Thus, larger motors with increased acceleration couldresult in the robots tilting excessively. Some embodiments of the singlecell robots have wheel hub motors of an in-wheel-motor configuration.The in-wheel configuration allows the wheel hub motor to fit inside thewheel and vehicle body so as not to occupy space within the cavity forreceiving storage containers. Thus, the prior art single cell robots donot have any available space for larger hub motors without impinging onthe storage container space inside the robot.

Consequently, the prior art solutions may have potential drawbacks inrelation to stability of the robots and or limited space for larger,more powerful wheel motors, in particular for single cell robots, wheremotors can be of the so called in-wheel-motor configuration in order tobe as small as possible to fit in the wheel and vehicle body while notoccupying the cavity for receiving storage containers.

In view of the above, it is desirable to provide a container handlingvehicle, an automated storage and retrieval system comprising saidcontainer handling vehicle, that solve or at least mitigate one or moreof the aforementioned problems related to the robots.

In particular, it is an objective of the present invention to provide arobot with improved acceleration and/or speed in at least one direction.

A further object of the invention is to provide a robot having a liftingdevice with improved acceleration, lifting capacity and/or speed.

SUMMARY OF THE INVENTION

The present invention is defined in the attached claims and in thefollowing.

It is described a container handling vehicle for picking up storagecontainers from a three-dimensional grid of an underlying storagesystem, comprising

-   -   a first set of wheels for moving the vehicle along an X        direction on a rail system of the grid; and    -   a second set of wheels for moving the vehicle along a Y        direction on the rail system of the grid, the Y direction being        perpendicular to the X direction;    -   a vehicle body comprising sides, the vehicle body having a        vehicle body footprint defined by horizontal peripheries in the        X and Y directions of the vehicle body, the vehicle body        comprising a first section and a second section, the first        section having a first footprint and the second section having a        second footprint, the first and second footprints being defined        by horizontal peripheries in the X and Y directions of the first        and second sections respectively;    -   wherein:    -   the first section and the second section are arranged        side-by-side, separated by a separation element of the first        section, such that a total area of the first and second        footprints equals a total area of the vehicle body footprint,        and a centre point of the first footprint is arranged off centre        relative a centre point of the vehicle body footprint;    -   the first section defines a storage container receiving space        which is configured to accommodate a storage container;    -   wherein the second section has a rectangular footprint and        comprises a portion of a first side of the vehicle body and an        opposed portion of a second side of the vehicle body, the second        section extending adjacent the separation element, wherein two        wheels are mounted to the separation element, one wheel is        mounted to the portion of the first side of the vehicle body and        one wheel is mounted to the portion of the second side of the        vehicle body, wherein the wheels mounted to said portions of the        first and second sides of the vehicle body are driven by a wheel        motor that extends from an interior face of the side of the        vehicle body into an internal space within the second section.

One of the advantages of the container handling vehicle is that it doesallow deeper wheel motors to be used in the second section. The wheelmotors may be fitted with direct drive motors which are deeper than thethickness of the sides of the container handling vehicle around thesecond section. Furthermore, providing wheel motors, which extend inthis way into an internal space within the second section, on only thewheels on the portion of the first side and the portion of the secondside and not on the wheels mounted to the separation element, which cancorrespond in depth to the thickness of the separation element, allowsfor even deeper motors (because the wheel motors are not limited by thewheel motors on the wheels mounted on the separation element).

Each of the wheels in the portion of the first side and the portion ofthe second side of the vehicle body may be connected to a separate wheelmotor.

The first side of the vehicle body may be common to the first and secondsections. The second side of the vehicle body may also be common to thefirst and second sections.

Alternatively both of the wheels mounted to the portion of the firstside and the portion of the second side of the vehicle body may bedriven by a common wheel motor.

One or more of the wheels mounted to the separation element may benon-motorized.

Alternatively each of the wheels mounted to the separation element maybe driven by wheel motors.

Each of the wheel motors may extend into an internal space of the secondsection, which internal space may be delimited on three sides by theseparation element, the interior face of the portion of the first sideand the interior face of the portion of the second side of the vehiclebody.

A size ratio of the first footprint relative the second footprint may beat least 2:1. Preferably, the size ratio of the first footprint relativethe second footprint may be 3:1, even more preferably the size ratio ofthe first footprint relative the second footprint may be 4:1, even morepreferably the size ratio of the first footprint relative the secondfootprint may be 5:1, even more preferably the size ratio of the firstfootprint relative the second footprint may be 6:1, even more preferablythe size ratio of the first footprint relative the second footprint maybe 7: 1. In general, smaller extent of the second section in the Ydirection, i.e. the narrower the section is and generally the morestable container handling vehicle will be when traveling in X direction.The X direction is the direction where the wheels in the second sectionare not in contact with the underlying rail system, and so the secondsection overhangs the wheelbase of the set of wheels (the first set ofwheels) that are in contact with the rails at that point.

The first set of wheels may be arranged on opposite sides of the firstsection and the second set of wheels may be arranged on opposite sidesof the vehicle body.

The first set of wheels comprises four wheels in total. The four wheelsare arranged as two pairs of wheels for movement in the X direction,where the wheels of each pair are arranged on opposite sides of thefirst section.

The second set of wheels comprises four wheels in total. The four wheelsare arranged as two pairs of wheels for movement in the Y direction,where the wheels of each pair are arranged on opposite sides of thevehicle body (which may also be on opposite sides of the first section).

The wheel motors driving the wheels mounted to the separation elementmay have a relatively lower power and/or acceleration compared to thewheel motors driving the wheels mounted on the portion of the first sideand the portion of the second side of the vehicle body.

The wheel motors may comprise hub motors providing direct drive on thewheels.

It is also described a container handling vehicle for picking up storagecontainers from a three-dimensional grid of an underlying storagesystem, comprising

-   -   a first set of wheels arranged at opposite portions of a vehicle        body of the container handling vehicle, for moving the vehicle        along a first direction on a rail system of the grid; and    -   a second set of wheels arranged at opposite portions of the        vehicle body, for moving the vehicle along a second direction on        the rail system of the grid, the second direction being        perpendicular to the first direction;    -   wherein    -   the vehicle body comprises walls (the walls being substantially        vertical) on all sides forming a footprint defined by horizontal        peripheries in the X and Y directions of the vehicle body, and        the container handling vehicle further comprises:    -   a first section and a second section arranged side-by-side such        that a centre point of a footprint of the first section is        arranged off centre relative a centre point of the footprint FV        of the vehicle body, and    -   wherein a size ratio of the footprint F1 of the first section        relative a footprint F2 of the second section is at least 2:1,        and wherein    -   the first section is configured to accommodate a storage        container,    -   the second section comprises an assembly of motors for driving        at least one wheel of each of the sets of wheels.

The container handling vehicle may also be defined as a containerhandling vehicle for picking up storage containers from athree-dimensional grid of an underlying storage system, comprising

-   -   a first set of wheels arranged at opposite portions of a vehicle        body of the container handling vehicle, for moving the vehicle        along a first direction on a rail system of the grid; and    -   a second set of wheels arranged at opposite portions of the        vehicle body, for moving the vehicle along a second direction on        the rail system of the grid, the second direction being        perpendicular to the first direction;    -   wherein    -   the vehicle body comprises walls (the walls being substantially        vertical) on all sides forming a footprint defined by horizontal        peripheries in the X and Y directions of the vehicle body, and        the container handling vehicle further comprises:    -   a first section and a second section arranged side-by-side such        that a centre point of a footprint of the first section is        arranged off centre relative a centre point of the footprint FV        of the vehicle body, and    -   wherein a size ratio of the footprint F1 of the first section        relative a footprint F2 of the second section is at least 2:1,        and wherein    -   the first section is configured to accommodate a storage        container,    -   the second section comprises any of multiple hub motors for        driving two wheels of each of the set of wheels, a motor for        driving a lifting device and/or rechargeable batteries.

The first section may comprise a cavity for accommodating a storagecontainer, and a lifting device arranged at a top section/upper level ofthe cavity.

The first set of wheels may be displaceable in a vertical directionbetween a first position, where the first set of wheels allow movementof the vehicle along the first direction, and a second position, wherethe second set of wheels allow movement of the vehicle along the seconddirection.

The assembly of motors may comprise at least one first motor for drivingthe first set of wheels and at least one second motor for driving thesecond set of wheels.

The container handling vehicle may comprise a lifting device for pickingup storage containers from the three-dimensional grid and the assemblyof motors comprises a lifting device motor connected to the liftingdevice.

The first section may accommodate a first, second, third and fourthwheel of the first set of wheels and a first and second wheel of thesecond set of wheels, and the second section may accommodate a third andfourth wheel of the second set of wheels.

The first section may accommodate a first and third wheel of the firstset of wheels and a first and second wheel of the second set of wheels,and the second section may accommodate a second and a fourth wheel ofthe first set of wheels and a third and a fourth wheel of the second setof wheels.

The first section may comprise four corners, and rims of the first,second, third and fourth wheels of the first set of wheels and the firstand second wheels of the second set of wheels may extend to the cornersof the first section.

The at least one first motor may comprise a hub motor for each of thefirst and fourth wheel of the first set of wheels, and the at least onesecond motor may comprise a hub motor for each of the third and fourthwheel in the second set of wheels. In other words, each of the first andfourth wheel of the first set of wheels, and each of the third andfourth wheel in the second set of wheels, may be driven by aseparate/dedicated hub motor.

The first and second sets of wheels may be arranged at or within alateral extent of the vehicle body.

The footprint of the first section may correspond to a grid cell of therail system, and, during use, when the container handling vehicle is ina position to lift or lower a storage container, the second section maybe horizontally displaced relative the grid cell and extend partly intoa neighbouring grid cell.

The assembly of motors may comprise multiple hub motors and each of thefirst and fourth wheel of the first set of wheels, and the third andfourth wheel of the second set of wheels, may comprise a separate hubmotor. Preferably, the hub motors of the first and fourth wheel of thefirst set of wheels, and the third and fourth wheel of the second set ofwheels, extend into an internal space in the second section.

It is further described an automated storage and retrieval systemcomprising a three-dimensional grid and at least one container handlingvehicle as described above, the grid comprises a rail system, on whichthe container handling vehicle may move, and a plurality of stacks ofstorage containers;

-   -   the rail system comprises a first set of parallel tracks        arranged in a horizontal plane and extending in a first        direction, and a second set of parallel tracks arranged in the        horizontal plane and extending in a second direction which is        orthogonal to the first direction, wherein the first and second        sets of tracks form a grid pattern in the horizontal plane        comprising a plurality of adjacent grid cells, each grid cell        comprising a grid opening defined by a pair of opposed tracks of        the first set of tracks and a pair of opposed tracks of the        second set of tracks;    -   the plurality of stacks of storage containers are arranged in        storage columns located beneath the rail system, wherein each        storage column is located vertically below a grid opening;    -   the first footprint is substantially equal to a grid cell        defined by a cross-sectional area, including width of the        tracks, between a pair of opposed tracks of the first set of        tracks and a pair of opposed tracks of the second set of tracks,        and the second section extends partially into a neighbouring        grid opening when the first section is positioned over an        adjacent grid opening.

An extent of the footprint of the container handling vehicle in the Xdirection, LX, and Y direction, LY, may be:

-   -   LX=1.0 grid cell in the X direction, and    -   1<LY<1.5 grid cells in the Y direction,        wherein a grid cell is defined as the cross-sectional area,        including width of the tracks, between the midpoint of two rails        running in the X direction and the midpoint of two rails running        in the Y direction.

The second section may extend less than 50% into the neighboring gridopening, more preferably less than 40% into the neighboring gridopening, even more preferably less than 30% into the neighboring gridopening, even more preferably less than 20% into the neighboring gridopening.

As indicated above, the container handling vehicle has a first andsecond section. The footprint of the first section can be equal to thesize of an underlying grid cell, and the second section is a protrudingsection which extends horizontally beyond the footprint of the firstsection.

A grid cell opening may be defined as the open cross-sectional areabetween two opposed rails running in the X direction and two opposedrails running in the Y direction.

The footprint of the second section may be less than half the size thefootprint of the first section (size ratio less than 1:2 relative thefirst section). When the container handling vehicle is positioned abovea grid cell in a position where it can lift or lower a storage containerinto or out of the first section, the second section extends into aneighboring grid cell. However, the footprint of the vehicle body isless than 1.5 cells (in the Y-direction) and maximum one grid cell widein the other direction (X-direction). In other words, the lateral extentof the container handling vehicle in the first direction corresponds tothe lateral extent of the tracks in one cell, and maximum 1.5 grid cellsin the direction perpendicular to the first direction. Consequently, inan example system for storing and retrieving storage containers, wheretwo of the container handling vehicles described above are operated andare oriented in opposite directions, they occupy three grid cells whentraveling in the first direction e.g. in the X-direction, whereas whentraveling in the second direction e.g. in the Y-direction, they cantravel along neighboring rows of grid cells occupying two grid cells.

The first section of the container handling vehicle may comprise acavity for accommodating a storage container and a lifting devicearranged to transport a storage container vertically between a storageposition in a stack and a transport position inside the cavity. Thelifting device may comprise a gripping device being configured toreleasably grip a storage container; and a lifting motor beingconfigured to raise and lower the gripping device relative to thecavity.

The second section makes it possible to utilize larger and stronger hubmotors for driving at least some of the wheels than what is possible inthe prior art single cell robots, for example lifting device motors withat least 70% more axial depth and stronger e.g. at least 10% strongerlifting device motors.

Hub motors arranged in the second section (or extending into the secondsection) may be arranged with a limited distance between them. Due tothe smaller distance between the motors, fewer, e.g. one BrushLessDirect Current (BLDC) card, may be required instead of four BLDC cardsin the prior art single cell robots. In the prior art solutions, thedistance between the motors driving the wheels in the container handlingvehicle is of such an extent that typically four BLDC cards arerequired. The cost of BLDC cards is quite high. However, as the distancebetween the motors can be substantially reduced by arranging the motorsin the second section, the overall cost for the container handlingvehicle can be reduced because fewer BLDC cards (e.g. only one BLDCcard) is required.

The container handling vehicle may comprise an exchangeable battery. Theexchangeable battery can be arranged in an upper portion of the vehicle,above the container storage compartment and lifting device. The exchangesequence of the exchangeable battery may include the following steps:

-   -   the vehicle or overall control system decides that the battery        shall be replaced,    -   the vehicle is operated to move to a battery exchange station,    -   the exchangeable battery is removed from a battery housing,    -   the vehicle is operated to move to a battery exchange station        having a charged battery using e.g. a capacitor power supply        arranged in a controller box in the vehicle,    -   the charged battery is installed into the battery housing,    -   the vehicle is ready for use.

In the following, numerous specific details are introduced by way ofexample only to provide a thorough understanding of embodiments of theinvention. One skilled in the relevant art, however, will recognize thatthese embodiments can be practiced without one or more of the specificdetails, or with other components, systems, etc. In other instances,well-known structures or operations are not shown, or are not describedin detail, to avoid obscuring aspects of the disclosed embodiments.

In the present disclosure relative terms such as upper, lower, lateral,vertical, X-direction, Y-direction, Z-direction, etc., shall beinterpreted using the above mentioned prior art storage system (FIG. 1)as a reference system. Therefore, the feature lateral in relation to theextent in the X-direction and Y-direction of the vehicle shall beunderstood to be the extent of the vehicle in the X-direction andY-direction, e.g. the footprint of the vehicle in the X-direction andY-direction.

SHORT DESCRIPTION OF THE DRAWINGS

Certain embodiments of the present invention will now be described indetail by way of example only and with reference to the followingdrawings:

FIG. 1 is a perspective side view of a prior art storage and retrievalsystem;

FIGS. 2A and 2B depict two different prior art container handlingvehicles and FIG. 2C shows the prior art container handling vehicle ofFIG. 2B in a second configuration;

FIGS. 3 and 4A are top schematic views of two types of rail systems foruse in the storage system in FIG. 1;

FIGS. 4B and 4C are top views of a rail system similar to FIG. 4Aillustrating the extent of a grid cell and the extent of a single cellvehicle operating on it;

FIG. 5A is an expanded perspective side view of parts of an exemplarylifting device which can be mounted in a container handling vehicle andan associated container which can be lifted by it;

FIGS. 5B, 5C, 5D show the footprints of an exemplary container handlingvehicle FV, the first section F1 and the second section F2, where thefootprints in each case are shown by the shaded area, respectively;

FIG. 6A is an angled side view from above of a container handlingvehicle;

FIG. 6B is a top view of the container handling vehicle of FIG. 6A andillustrates the extent in the X- and Y-directions of the containerhandling vehicle on a rail system;

FIG. 7 is a top view of three such container handling vehicles passingeach other and operating on a rail system;

FIG. 8A is a perspective view from below of an interior of the containerhandling vehicle with the lifting device in an upper position inside afirst section;

FIG. 8B is a perspective view from below of an interior of the containerhandling vehicle with some details omitted and the lifting device in alower position having been lowered from a first section;

FIG. 9 is a side view of the container handling vehicle of FIG. 8A withtwo batteries visible in a second section;

FIG. 10A is a perspective side view of the container handling vehicle ofFIG. 8A with certain details omitted including the covers which havebeen removed to reveal internal details, for example, an exchangeablebattery arranged inside a battery receiving unit in an upper portion ofthe container handling vehicle;

FIG. 10B is another perspective view of the container handling vehicleof FIG. 10A, where an assembly of motors including a lifting devicemotor can be seen in the second section;

FIG. 10C is perspective view of an alternative container handlingvehicle of FIG. 10B, where a lifting device motor and angledtransmission (angled gear) can be seen in the second section;

FIGS. 10D and 10E are different views of an alternative containerhandling vehicle of FIG. 10C, where the lifting device motor and anglegear are rotated 90 degrees relative the lifting device motor and angledtransmission of FIG. 10C;

FIGS. 10F and 10G are perspective views of an alternative containerhandling vehicle of FIG. 10B, where a lifting device motor and hollowshaft gear can be seen in the second section;

FIG. 10H is an exploded view of a hollow shaft gear used to connect thelifting device motor and the lifting axle;

FIG. 10I is a side view of a container handling vehicle with wheelmotors on the wheels in the Y direction in the second section;

FIG. 10J is a view from below a container handling vehicle showinglarger wheel motors only on the wheels in the Y direction in the secondsection;

FIG. 10K is a side view into the second section in an Y direction of thecontainer handling vehicle;

FIG. 11A is a side perspective view of two container handling vehiclespassing each other in the X direction of a rail system;

FIG. 11B is a top perspective view of FIG. 11A;

FIG. 11C is another side view of FIG. 11A, showing a gap between the twocontainer handling vehicles passing each other in the X direction of therail system;

FIG. 11D shows a perspective view from below of the container handlingvehicles;

FIGS. 12A-C show differences in the center of gravity of the storagecontainers inside the storage container cavity relative the center ofthe footprint of the vehicle body, where FIG. 12A illustrates a priorart single cell robot, FIG. 12B is a prior art central cavity robot, andFIG. 12C shows a container handling vehicle according to the presentinvention;

FIGS. 13A-C show differences in imaginary lines extending between eachof two pairs of opposed wheels of the same sets of wheels, and which ofsaid lines which intersect or not intersect imaginary lines betweenother wheels, where FIG. 13A illustrates a prior art single cell robot,FIG. 13B is a prior art central cavity robot, and FIG. 13C shows acontainer handling vehicle according to the present invention.

FIG. 13D shows a possible setup of centres of wheel bases for the firstset of wheels and the second set of wheels, respectively, and that saidwheel bases are off-centre relative each other;

In the drawings, like reference numbers have been used to indicate likeparts, elements or features unless otherwise explicitly stated orimplicitly understood from the context.

DETAILED DESCRIPTION OF THE INVENTION

In the following, embodiments of the invention will be discussed in moredetail by way of example only and with reference to the appendeddrawings. It should be understood, however, that the drawings are notintended to limit the invention to the subject-matter depicted in thedrawings and that features described in one drawing are not necessarilydependent on the presence of other features shown in the same drawingbut can be combined with features from embodiments of other drawings.

Referring to FIGS. 3 to 4C, top views of two different rail systems ofthe automated storage and retrieval systems are shown.

The rail system forms a grid structure or grid pattern in the horizontalplane P, see FIG. 1. The grid 4 comprises a plurality of rectangular anduniform grid locations or grid cells 14 (see FIG. 4B), where each gridcell 14 comprises a grid opening 15 (i.e. the upper end of a storagecolumn 12) which is delimited by a pair of opposed rails 10 a, 10 b of afirst set of tracks and a pair of opposed rails 11 a, 11 b of a secondset of tracks. The rails 10 a,10 b,11 a,11 b form a rail system 8 onwhich the container handling vehicle(s) 9′ operate. In FIG. 4B, the gridcell 14 is indicated by a dashed box and the grid opening 15 isindicated by a hatched area.

Consequently, pairs of opposed rails 10 a and 10 b define parallel rowsof grid cells running in the X direction, and pairs of opposed rails 11a and 11 b extending perpendicular to rails 10 a and 10 b defineparallel rows of grid cells running in the Y direction.

Each grid cell 14 has a width W_(c) which is typically within theinterval of 30 to 150 cm, and a length L_(c) which is typically withinthe interval of 50 to 200 cm. Each grid cell 14 may be rectangular asshown such that W_(c)<L_(c). Each grid opening 15 has a width W_(o) anda length L_(o) which is typically 2 to 10 cm less than the width W_(c),and the length L_(c), respectively, of the grid cell 14. This differencebetween W_(c) and W_(o) and between L_(c) and L_(o) corresponds to thewidth (i.e. the width of a set of tracks) of two opposed rails 10 a,10b,11 a,11 b or, in effect, the width of a double-track rail since thegrid cell extends to the midpoint of such a double-track rail (i.e. adouble-track rail comprising 10 a and 10 b or 11 a and 11 b).

The double-track rail may be profiled to provide two parallel channelsfor the wheels of the container handling vehicle to run in.

FIG. 3 shows a prior art rail system featuring single-track rails 10,11. When such a rail system is used, two container-handling vehicles arenot allowed to pass each other at adjacent grid cells 14.

Where a single-track rail is used in one of the directions, then theboundary of the grid cell extends to the side of the track on theopposite side of the grid opening to the one being worked (neighboringgrid cells will overlap by this track width in a similar way).

The rail system shown in FIGS. 4B and 4C, features horizontaldouble-track rails. Consequently, each rail is capable of accommodatingtwo wheels in parallel. In such a rail system, the borders betweenneighboring grid cells 14 run along the centre-line of the horizontalrails, as is indicated in FIG. 4B.

In FIG. 4C, grid cell 14, in the middle of the section of theillustrated grid system, comprises a grid opening/grid cell opening 15.To the left (West) of grid cell 14, there is an adjacent grid cell 14Wcomprising a grid opening 15W. Likewise, to the right (East) of gridcell 14, there is an adjacent grid cell 14E comprising a grid opening15E. Also, below grid cell 14 (South), there is an adjacent grid cell14S comprising a grid opening 15S, and above grid cell 14 (North), thereis an adjacent grid cell 14N comprising a grid opening 15N.

In FIG. 4C, a footprint 30 of a prior art container handling vehicle isschematically illustrated. In this embodiment the footprint 30 isdefined by the horizontal extent of the wheels of the vehicle. As isevident from the figure, the footprint 30 has a horizontal extent whichis less than the horizontal extent of a grid cell.

FIG. 5A is a perspective side view of parts of a lifting device 18 whichcan be mounted in a container handling vehicle and a container 6 to belifted by the lifting device. The lifting device comprises a liftingframe 17, which is commonly connected to at least one rotatable liftingshaft via lifting bands, the lifting shaft arranged at an upper levelwithin a cavity of the container handling vehicle. FIG. 5B shows thefootprint, i.e. the dashed area in the Figure denoted FV, of anexemplary container handling vehicle 9′ according to the invention. Thefootprint FV is equal to the lateral extent of the container handlingvehicle 9′ in both directions. The container handling vehicle 9′consists of a first section 204 and a second section 205.

FIG. 5C shows the footprint of the first section 204, i.e. the dashedarea in the Figure denoted F1. In the disclosed embodiment, the firstsection comprises a cavity for accommodating a storage bin 6 and alifting device 18 as shown in FIG. 5A. FIG. 5D shows the footprint ofthe second section 205, i.e. the dashed area in the Figure denoted F2.

FIG. 6A is a perspective side view from above of a container handlingvehicle 9′. The container handling vehicle 9′ operates on a rail system8, and is configured to move laterally in the X and Y directionsindicated in the Figure. The X direction is perpendicular to the Ydirection.

The vehicle 9′ comprises a first set of wheels (not shown, see FIG. 8A)arranged at opposite portions of a vehicle body 13, for moving thevehicle 9′ along a first direction X on a rail system 8 of a storagesystem 1, and a second set of wheels (only two of the wheels of thesecond set of wheels are shown, 202″,202″″) arranged at oppositeportions of the vehicle body 13, for moving the vehicle 9′ along asecond direction Y on the rail system 8. The second direction Y isperpendicular to the first direction X. The first set of wheels isdisplaceable in a vertical direction Z between a first position and asecond position. In the first position, the first set of wheels allowmovement of the vehicle 9′ along the first direction X, and in thesecond position, the second set of wheels allow movement of the vehicle9′ along the second direction Y. Structural details of suitableassemblies for providing displaceable sets of wheels are disclosed infor instance WO2015/193278 A1 and WO2017/153583, the contents of whichare incorporated by reference.

FIG. 6B is a top view of a container handling vehicle 9′ of FIG. 6A andillustrates the extent in the X- and Y directions (LX and LY) of thecontainer handling vehicle 9′ on a rail system 8. The line C indicates acenter line of the grid cell 14 and grid cell opening 15 in the Ydirection. The footprint of the container handling vehicle 9′ in the Xdirection (LX) is substantially equal to the dimension of the grid cell14 in the X direction and the footprint of the container handlingvehicle 9′ in the Y direction (line LY) is larger than the dimension ofthe grid cell 14 in the Y direction such that part of the vehicle bodyextends into a neighboring cell (in the embodiment shown, this is aneighbouring cell to the left of the cell being worked). This extensionof the vehicle body into the neighboring cell is of a size less thanhalf the lateral extent in the Y direction of the grid cell opening inthe neighboring cell, meaning that the length LY is more than 1.0 gridcell but less than 1.5 grid cells 14 in the Y direction (1.0<LY<1.5 gridcells).

When operating on a rail system 8 as shown in FIG. 6B with rectangulargrid cells 14, the footprint of the container handling vehicle 9′ issubstantially square because the extent of the grid cell 14 is longer inthe X direction than in the Y direction and the container handlingvehicle occupies more than one grid cell 14 in the Y direction and onlyone grid cell 14 in the X direction. A substantially square footprinthas the advantage that the overall stability of vehicle 9′ is improvedcompared to prior art solutions displaying a more rectangular footprintoften in combination with a relatively high center of gravity.

FIG. 7 is a top view of three similar container handling vehicles 9′oriented in the same direction, passing each other and operating on arail system 8 featuring dual-track rails as discussed above. As shown inthe Figure, the container handling vehicles 9′ have a footprintcorresponding to the dimension of the grid cell 14 in the X directionallowing other container handling vehicles 9′ traveling in the Ydirection, to pass in neighboring cells (the container handling vehicles9′ occupying two rows of the rail system 8 as they pass by each other)on both sides of the vehicle 9′. However, because the size of theoverlap into the neighboring cell is less than half the lateral extentof the grid cell in the Y direction, similar container handling vehicles9′ traveling in the X direction can pass each other occupying threerows.

The presence of the second section 205, makes it possible to utilizelarger and stronger motors 203, see FIG. 8A, for driving the wheels thanin the prior art single cell robot shown in FIG. 2A, while at the sametime keeping many of the advantages of such a robot.

As disclosed in FIG. 8A, the first section 204 accommodates a first201′, second 201″, third 201′″ and fourth 201″″ wheel of the first setof wheels and a first 202′ and second 202″ wheel of the second set ofwheels, and the second section accommodates a third 202′″ and fourth202″″ wheel of the second set of wheels. This particular wheelarrangement is highly advantageous as it allows for the use of morepowerful wheel hub motors 203 for driving the second 201″ and the fourth201″″ wheel of the first set of wheels as well as the third 202′″ fourth202″″ wheel of the second set of wheels.

Alternatively, the second 201″ and fourth 201″″ wheel of the first setof wheels can be accommodated in the second section (not shown) providedthe hub motors of said wheels are also arranged in the second section.To improve stability of the vehicle 9′, the rim of the wheels 201′,201′″, 202′, 202″, 202′″, 202″″ preferably extend to the corners of thevehicle 9′.

All of the wheels 201′, 201″, 201′″, 201″″, 202′, 202″, 202′″, 202″″ arepreferably arranged inside the lateral extent LX, LY in the X and Ydirections of the vehicle body 13 (see also description in relation toFIG. 9).

The first section 204 and the second section 205 may be fully separatedby a physical barrier at the intersection between the first and secondsections 204, 205, such as a wall or plate or similar. Alternatively,the first and second sections 204, 205 may be partly separated at theintersection between the first and second section 204, 205, for exampleby providing a barrier over parts of the intersection.

In FIG. 8A, the first and second section is separated by a wheelconnecting element 212 (i.e. a connection plate or beam) to which thesecond 201″ and the fourth 201″″ wheel of the first set of wheels andtheir respective hub motors 203 are connected. The wheel connectingelement 212 is part of a wheel displacement assembly 214, such that thesecond 201″ and the fourth 201″″ wheel of the first set of wheels(together with the first 201′ and the third 201″ wheel of the first setof wheels) may be moved in a vertical direction.

In the disclosed embodiment, the second 201″ and the fourth 201″″ wheelsare accommodated in the first section 204, while the hub motors 203extend into the second section. In an alternative embodiment, both thesecond 201″ and the fourth 201″″ wheels, as well as the hub motors, maybe accommodated in the second section 205.

It is noted that having the second 201″ and the fourth 201″″ wheel ofthe first set of wheels, as well as the third 202′″ fourth 202″″ wheelof the second set of wheels, arranged such that their hub motors 203extend/protrude into the second section 205 allows for the use of morepowerful motors than would be the case if the hub motors were arrangedsuch that they would extend into the first section 204. The remainingwheels, i.e. the wheels not featuring a hub motor extending into thesecond section, may either be passive or motorized, for instancemotorized by in-wheel hub motors as disclosed in WO 2016/120075 A1.

FIG. 8B is a perspective view from below of an interior of the containerhandling vehicle 9′ showing the lifting frame 17 of the lifting device18 in a lower position extending downwardly from the first section 204.The lifting device 18 may have similar features as the lifting devicedescribed in relation to FIGS. 2A and 2B.

FIG. 9 is a side view of a container handling vehicle with hub motors203 and two batteries 213′, 213″ arranged in the second section 205. Asis clear from e.g. FIG. 9, the exterior facing side of the wheels may inone aspect be arranged such that they are not extending outside thevehicle body 13 (indicated by the dotted lines on each side of thevehicle 9′ in FIG. 9). For example, the exterior facing sides of thewheels in the lateral X and Y directions may be flush with the vehiclebody 13. Although not shown in FIG. 9 (but in FIGS. 8A and 8B+6B), thesame applies to the wheels in the opposite direction (X), i.e. thosewheels may also be arranged such that they are not extending outside thevehicle body 13.

The vehicle body 13 includes any of the following elements, even if allare present or if some are missing, such as body frame, side coverpanels or plates, wheel suspensions, housing for track sensors betweenthe wheels etc. A rotating exterior surface of the wheels may thus bearranged in the same vertical plane as one of the walls in the vehiclebody 13. Alternatively, the wheels may be arranged inside the vehiclebody 13 such that the rotating exterior surfaces of the wheels can belaterally displaced relative a vertical plane formed by one of the wallsin the vehicle body 13. In FIG. 6B, none of the wheels are visible inthe top view, indicating that the outermost lateral parts of all wheelsare arranged such that they are not extending outside the vehicle body13.

The container handling vehicle 9′ may be provided with an interface 206(see FIG. 8A) for charging of the batteries 213′, 213″ in the containerhandling vehicle 9′.

FIG. 10A is a side view of a container handling vehicle 9′ where certainparts like the covers are removed. The container handling vehicle 9′ hasan exchangeable battery 208 arranged inside a battery receiving unit 209in an upper portion of the container handling vehicle. It is furtherdisclosed a controller unit 210 which communicates with the overallcontrol system. The controller unit 210 may further accommodate acapacitor power supply (not shown). The capacitor power supply typicallyhas the ability to store enough power to operate any of the electricallydriven components of the vehicle 9′ if the main power supplymalfunctions or is lost. Such situations may e.g. be when the battery208 is to be exchanged. The battery exchange is typically taking placeon two different locations, i.e. the battery to be replaced (the “empty”battery) is dropped off at a different location to where the replacementbattery is picked up from (“fully charged” battery), therefore thecapacitor power supply may be used to move the robot between the twodifferent locations. Alternatively, if the main battery malfunctions,the capacitor power supply can be used to operate the lifting deviceand/or move the robot to a service area. Furthermore, any regeneratedpower can be supplied to the capacitor power supply in order to makesure that the capacitor power supply has sufficient power capacity toperform any of its desired functions.

FIG. 10B is another view of FIG. 10A, where it is disclosed an assemblyof motors comprising a lifting device motor 211 arranged in the secondsection 205. The lifting device motor 211 is connected at one end of arotatable lifting shaft (not shown) of a lifting device arranged in thefirst section. This lifting device motor 211 may replace other liftingdevice motor(s) (not shown) arranged in the first section or function asan auxiliary motor in addition to any lifting device motors arranged inthe first section. Thus, the second section 205 makes it possible toreduce the number of lifting device motor(s) in the first section to aminimum (even avoid the use of a lifting device motor in the firstsection) because the size and lifting capacity of the lifting devicemotor 211 arranged in the second section 205 is not limited by theavailable space of the first section. In other words, the lifting devicemotor 211 in the second section may be the sole lifting device motor ofthe vehicle, such that the available space in a top section of the firstsection of the vehicle 9′ is increased, or the motor 211 may be anauxiliary motor providing an increased lifting capacity to the liftingdevice.

FIG. 10C shows an embodiment of a container handling vehicle 9′, whereinthe lifting device comprises a single lifting device motor 211′ andangled transmission 215 are arranged in the second section. Theembodiment serves to illustrate how the available space of the secondsection allows for the use of a more powerful (and consequently larger)lifting device motor 211′ than what would be possible to arrange in thefirst section alone. This allows for the use of storage containershaving a higher total weight (i.e. the weight including products storedin the container). It is noted that the prior art vehicle in FIGS. 2Band 2C would likely have available space for a similar large liftingdevice motor, but would not be able to fully utilize the possibility ofincreased lifting capacity due to the cantilever design. Again referringto FIG. 10C, the angled transmission 215 with connected lifting devicemotor 211′ is angled downwards (i.e. in a mainly vertical direction). Incontrast, as seen in FIGS. 10D and 10E, a similar embodiment as in FIG.10C is shown, however, the angled transmission 215 with connectedlifting device motor 211′ is angled sideways (i.e. in a mainlyhorizontal direction), rotated 90 degrees relative to the embodiment inFIG. 10C. Furthermore, FIG. 10E shows the lifting device axle 216 towhich axle lifting bands connected to the lifting device 18 (not shownin FIG. 10E) are connected and coils up and reels out during lifting andlowering of the lifting device.

FIGS. 10F and 10G are perspective views of an alternative containerhandling vehicle of FIG. 10B, where the lifting device motor 211′ and ahollow shaft gear 215 are arranged in the second section.

The configuration of the lifting device motor 211′ in FIGS. 10B and 10Crender possible the use of two lifting device motors 211, 211′ connectedto respective lifting axles 216 (only one lifting axle shown in theFigures). Such a setup, i.e. two lifting device motors 211, 211′arranged at opposite sides in the second section will provide a morestable container handling vehicle 9′ as the weight distribution from thelifting device motors 211, 211′ will be more advantageous in terms ofthe overall centre of gravity for the container handling vehicle 9′.

FIG. 10H is an exploded view of a hollow shaft gear 215 used to connectthe lifting device motor 211′ and lifting device axle 216. Compared tothe embodiment of FIGS. 10C-10E, the lifting axle 217 of FIGS. 10F-10Hhas been extended and the gear 215 is connected directly to the extendedlifting axle 217 without a dedicated connection. To be able to make thisdirect connection, a hollow shaft gear 215 is used instead of an angledtransmission. The hollow shaft gear 215 can be secured to the extendedlifting axle 217 using dedicated means, such as e.g. as shown in theFigure where a clamp and wedge configuration is used.

FIG. 10I is a side view of a container handling vehicle 9′ with wheelmotors 203 on the wheels 202′″, 202″″ in the Y direction in the secondsection 205 and not on the wheels 201″, 201″″ in the X direction on theseparation element 212.

FIG. 10J is a view from below a container handling vehicle 9′ showinglarger wheel motors 203 only on the wheels 202′″, 202″″ in the Ydirection in the second section 205 and not on the wheels 201″, 201″″ inthe X direction on the separation element 212. As is best shown in FIG.10J, the separation element 212 of the first section 204 divides theinterior of the container handling vehicle 9′ in the first and secondsections 204, 205. Two wheels 201″, 201″″ in the X direction are mountedon the separation element 212.

FIG. 10K is a side view into the second section in an Y direction of thecontainer handling vehicle 9′.

As is clear from FIGS. 10I-10K, the second section 205 is relativelysmaller, i.e. less deep, than the second section 205 in e.g. FIGS.10F-H.

As indicated above, in all FIGS. 10I-10K, the first section 204 is ofthe same size as the first section 204 of the container handling vehicle9′ in e.g. FIGS. 10F-10H and the second section 205 is smaller, i.e. itis less deep and has a relatively smaller extent in the Y direction,than the second section 205 of the container handling vehicle 9′ inFIGS. 10F-10H. The setup and relatively small size (i.e. small extent inthe Y direction) of the second section 205 in FIGS. 10I-10K has anadvantage in that the cantilever or overhang formed of the secondsection 205 when the container handling vehicle is running in the Xdirection has minimum impact on the stability of the container handlingvehicle 9′.

The radial and longitudinal extent of the wheel motors 203 in the secondsections are adapted to fit into the available internal space in the Xdirection and Y direction of the second section 205. As shown in FIGS.10I-10K, the radial/diameter extent of the wheel motors 203 are dictatedby the extent of the second section in the Y direction (limited by theseparation element between the first and second section 204, 205 and thevehicle body 13. The wheel motors 203 extend into an internal space inthe second section 205, which internal space is delimited by theseparation element 212 and the three sides of the vehicle body 13forming three of the outer boundaries for the second section 205. Thedepth of the wheel motors 203 (i.e. the extent of the wheel motors 203in the X direction) is limited by the width LX in the X direction andcan be significantly larger than the width LY of the second section 205in the Y direction, for example up to 50% larger and more, such as 60%,70%, 80 and up to 90% larger.

FIG. 11A is a side view of two container handling vehicles 9′ travelingin the X direction of the rail system 8 passing each other using a totalof three cells in the Y direction of the rail system 8. This particularrail system comprises single track rails in the X direction anddouble-track rails in the Y direction. The combination of single- anddouble-track rails may in some instances be the most cost-efficientsolution, even if a rail system using only double-track rails is optimalregarding the possible travel paths of the container-handling vehiclesarranged thereon.

FIG. 11B is a top view of FIG. 11A showing a gap G between the vehiclebodies 13 in the Y direction rendering possible the two vehicles 9′traveling in the X direction to occupy only three rows in the Ydirection.

FIGS. 12A-C show differences in the center of gravity of the storagecontainers inside the storage container cavity relative the center ofthe footprint of the vehicle body, where FIG. 12A illustrates a priorart single cell robot, FIG. 12B is a prior art central cavity robot, andFIG. 12C shows an exemplary container handling vehicle according to thepresent invention.

In a single cell and central cavity robot, FIG. 12A, the center ofgravity of the storage container CGSC is in the center of the cavitywhich also coincides with the center of the footprint of the vehiclebody CGV.

In in a central cavity robot, FIG. 12B, the center of gravity of storagecontainer CGSC is in the center of the cavity which also coincides withthe center of the footprint of the vehicle body CGV.

FIG. 12C shows an exemplary container handling vehicle according to thepresent invention, where the center of gravity of storage container CGSCis displaced relative the center of the footprint of the vehicle bodyCGV.

FIGS. 13A-C are plan views showing differences in imaginary linesextending between wheel pairs of the same sets of wheels, and how saidlines intersect, or not, imaginary lines between other wheels. FIG. 13Aillustrates a prior art single cell robot, FIG. 13B is a prior artcentral cavity robot, and FIG. 13C shows an exemplary container handlingvehicle according to the present invention.

In FIG. 13A, in a single cell and central cavity robot, each imaginaryline L1, L2, L3, L4 extending between each of two pairs of opposedwheels in each set of wheels intersects two other imaginary lines L1,L2, L3, L4.

In FIG. 13B, in a central cavity robot, none of the imaginary lines L1,L2, L3, L4 extending between each of two pairs of opposed wheels in eachset of wheels intersects another imaginary line L1, L2, L3, L4.

FIG. 13C shows an exemplary container handling vehicle according to thepresent invention where imaginary lines L1, L2 between each of two pairsof opposed wheels in the first set of wheels intersect one imaginaryline L3 extending between two wheels in the second set of wheels, andwhere one imaginary line L4 between two wheels in the second set ofwheels does not intersect any imaginary lines.

FIG. 13D shows a possible setup of centres of wheel bases for the firstset of wheels and the second set of wheels, respectively, and that saidwheel bases are off-centre relative each other. The wheel base of thefirst set of wheels 22 (comprising two wheel pairs where a first wheelpair comprises wheels denoted 201′, 201″ and a second wheel paircomprises wheels 201′″ and 201″″) has a centre CWB1 and the wheel baseof the second set of wheels 23 (comprising two wheel pairs where a firstwheel pair comprises opposite wheels denoted 202′, 202″ and a secondwheel pair comprises opposite wheels 202′″ and 202″″) has a centre CWB2.The wheels 201′-201″″ in the first set of wheels 22 are arranged onopposite sides of the first section 204 and the wheels 202′-202″″ in thesecond set of wheels 23 are arranged on opposite sides of the vehiclebody 13. The centre CWB2 of the second set of wheels 23 coincides withthe centre of the vehicle body 13.

The first set of wheels 22 comprises four wheels 201′,201″,201′″,201″″in total. The four wheels 201′,201″,201′″,201″″ in the first set ofwheels 22 are arranged as two pairs of wheel for movement in the Xdirection, where the wheels 201′,201″; 201′″,201″″ of each pair arearranged on opposite sides of the first section 204.

The second set of wheels 23 comprises four wheels 202″,202″,202′″,202″″in total. The four wheels 202′,202″,202′″,202″″ are arranged as twopairs of wheels in the Y direction, where the wheels202′,202″;202′″,202″″ of each pair are arranged on opposite sides of thevehicle body 13 (which may also be on opposite sides of the firstsection).

The invention has been described with reference to the Figures, howeverthe skilled person will understand that there may be made alterations ormodifications to the described embodiments without departing from thescope of the invention as described in the attached claims.

Reference numerals (1) underlying storage system/frame structure (3)horizontal member (4) three-dimensional grid, storage grid (5) storagecolumn (6, 6′) storage container/storage bin (7) stacks (8) rail system(9, 9′) container handling vehicle, vehicle (10) first set of rails ortracks (11) second set of rails or tracks (10, 10b) track in X direction(11a, 11b) track in Y direction (12) grid column (13) vehicle body (14)grid cell (14E) adjacent grid cell (14N) adjacent grid cell (14S)adjacent grid cell (14W) adjacent grid cell (15) grid opening/grid cellopening (15E) grid opening (15N) grid opening (15S) grid opening (15W)grid opening (17) lifting frame (18) lifting device (19) first portcolumn (19) drop-off port (20) second port (20) pick-up port (21) cavity(22) first set of wheels (23) second set of wheels (30) footprint priorart container handling vehicle (201′) first wheel first set of wheels(201″) second wheel first set of wheels (201″′) third wheel first set ofwheels (201″″) fourth wheel first set of wheels (202′) first wheelsecond set of wheels (202″) second wheel second set of wheels (202″′)third wheel second set of wheels (202″″) fourth wheel second set ofwheels (203) first wheel motor (203) second wheel motor (203) assemblyof wheel motors (204) first section (205) second section (206) interface(208) battery (209) battery receiving unit (210) controller unit (211′)lifting device motor (212) separation element/wheel connecting element(213′, 213″) batteries (214) wheel displacement assembly (215) Hollowshaft gear/angled transmission (216) Lifting device axle (217) Extendedlifting axle (P) horizontal plane (X) X direction/first direction (Y) Ydirection/second direction (Z) vertical direction (FV) footprint ofcontainer handling vehicle (F1) footprint first section (F2) footprintsecond section (L1) imaginary line (L2) imaginary line (L3) imaginaryline (L3) imaginary line (L4) imaginary line (CGSC) center of gravitystorage container (CGV) center of footprint vehicle body (LX) lateralextension, length X direction (LY) lateral extension, length Y direction(CWB1) centre wheel base first set of wheels (CWB2) centre wheel basesecond set of wheels

The invention claimed is:
 1. A container handling vehicle for picking upstorage containers from a three-dimensional grid of an underlyingstorage system, comprising: a first set of wheels for moving the vehiclealong an X direction on a rail system of the grid; a second set ofwheels for moving the vehicle along a Y direction on the rail system ofthe grid, the Y direction being perpendicular to the X direction; and avehicle body comprising sides, the vehicle body having a vehicle bodyfootprint defined by horizontal peripheries in the X and Y directions ofthe vehicle body, the vehicle body comprising a first section and asecond section, the first section having a first footprint and thesecond section having a second footprint, the first and secondfootprints being defined by horizontal peripheries in the X and Ydirections of the first and second sections respectively; wherein: thefirst section and the second section are arranged side-by-side,separated by a separation element of the first section, such that atotal area of the first and second footprints equals a total area of thevehicle body footprint, and a centre point of the first footprint isarranged off centre relative a centre point of the vehicle bodyfootprint; the first section defines a storage container receiving spacewhich is configured to accommodate a storage container; the first set ofwheels is arranged on opposite sides of the first section and the secondset of wheels is arranged on opposite sides of the vehicle body; and thesecond section has a rectangular footprint and comprises a portion of afirst side of the vehicle body and an opposed portion of a second sideof the vehicle body, the second section extending adjacent theseparation element, wherein two wheels are mounted to the separationelement, one wheel is mounted to the portion of the first side of thevehicle body and one wheel is mounted to the portion of the second sideof the vehicle body, wherein the wheels mounted to said portions of thefirst and second sides of the vehicle body are driven by a wheel motorthat extends from an interior face of the side of the vehicle body intoan internal space within the second section.
 2. The container handlingvehicle according to claim 1, wherein each of the wheels mounted to theportion of the first side and the portion of the second side of thevehicle body are connected to separate wheel motors.
 3. The containerhandling vehicle according to claim 1, wherein the first side of thevehicle body is common to the first and second sections and the secondside of the vehicle body is common to the first and second sections. 4.The container handling vehicle according to claim 1, wherein both of thewheels mounted to the first portion and the second portion of sides ofthe vehicle body are driven by a common wheel motor.
 5. The containerhandling vehicle according to claim 1, wherein the wheels mounted to theseparation element are non-motorized.
 6. The container handling vehicleaccording to claim 1, wherein each of the wheels mounted to theseparation element are driven by wheel motors.
 7. The container handlingvehicle according to claim 6, wherein the wheel motors driving thewheels mounted to the separation element have a relatively lower powerand/or acceleration compared to the wheel motors driving the wheelsmounted the first portion and the second portion of the side of thevehicle body.
 8. The container handling vehicle according to claim 1,wherein each of the wheel motors extends into an internal space of thesecond section, which space is delimited on three sides by theseparation element, the interior face of the portion of the first sideand the interior face of the portion of the second side of the vehiclebody.
 9. The container handling vehicle according to claim 1, whereinthe wheel motors comprise hub motors providing direct drive on thewheels.
 10. A container handling vehicle according to claim 1, wherein asize ratio of the first footprint relative the second footprint is atleast 2:1.
 11. An automated storage and retrieval system comprising athree-dimensional grid and at least one container handling vehicleaccording to claim 1, the grid comprises a rail system, on which thecontainer handling vehicle may move, and a plurality of stacks ofstorage containers; the rail system comprises a first set of paralleltracks arranged in a horizontal plane and extending in an X direction,and a second set of parallel tracks arranged in the horizontal plane andextending in a Y direction which is orthogonal to the X direction,wherein the first and second sets of tracks form a grid pattern in thehorizontal plane comprising a plurality of adjacent grid cells, eachgrid cell comprising a grid opening defined by a pair of opposed tracksof the first set of tracks and a pair of opposed tracks of the secondset of tracks; the plurality of stacks of storage containers arearranged in storage columns located beneath the rail system, whereineach storage column is located vertically below a grid opening; thefirst footprint is substantially equal to a grid cell defined by across-sectional area, including width of the tracks, between a pair ofopposed tracks of the first set of tracks and a pair of opposed tracksof the second set of tracks, and the second section extends partiallyinto a neighboring grid opening when the first section is positionedover an adjacent grid opening.
 12. An automated storage and retrievalsystem according to claim 11, wherein an extent of the footprint of thecontainer handling vehicle in the X direction, LX, and Y direction, LY,is: LX=1.0 grid cell in the X direction, and 1<LY<1.5 grid cells in theY direction, wherein a grid cell is defined as the cross-sectional area,including width of the tracks, between the midpoint of two rails runningin the X direction and the midpoint of two rails running in the Ydirection.